Just as farsightedness is often age-related, sensorineural hearing loss (SNHL) also occurs as a natural part of growing old; it accounts for about 90% of all hearing loss.
SNHL is commonly caused by damage to the inner ear (the cochlea), or by damage to the nerve pathway from the inner ear to the brain. As a result, signals reaching the brain lack vital auditory information, making speech unintelligible and sounds inaudible.
Apart from aging, SNHL may also be caused by exposure to loud sounds, head injuries, genetics, diseases, tumors, and certain powerful medications.